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Question 1
Correct
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A 65-year-old man presents to the clinic with a complaint of losing 1 stone in weight over the past three months. Apart from this, he has no significant medical history. During the physical examination, his abdomen is soft, and no palpable masses are detected. A normal PR examination is also observed. The patient's blood tests reveal a haemoglobin level of 80 g/L (120-160) and an MCV of 70 fL (80-96). What is the most appropriate initial investigation for this patient?
Your Answer: Upper GI endoscopy and colonoscopy
Explanation:Possible GI Malignancy in a Man with Weight Loss and Microcytic Anaemia
This man is experiencing weight loss and has an unexplained microcytic anaemia. The most probable cause of his blood loss is from the gastrointestinal (GI) tract, as there is no other apparent explanation. This could be due to an occult GI malignancy, which is why the recommended initial investigations are upper and lower GI endoscopy. These tests will help to identify any potential sources of bleeding in the GI tract and determine if there is an underlying malignancy. It is important to diagnose and treat any potential malignancy as early as possible to improve the patient’s prognosis. Therefore, prompt investigation and management are crucial in this case.
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This question is part of the following fields:
- Gastrointestinal System
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Question 2
Incorrect
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Secretions from which of the following will contain the highest levels of potassium?
Your Answer: Gallbladder
Correct Answer: Rectum
Explanation:The rectum can produce potassium-rich secretions, which is why resins are given to treat hyperkalemia and why patients with villous adenoma of the rectum may experience hypokalemia.
Potassium Secretions in the GI Tract
Potassium is secreted in various parts of the gastrointestinal (GI) tract. The salivary glands can secrete up to 60mmol/L of potassium, while the stomach secretes only 10 mmol/L. The bile, pancreas, and small bowel also secrete potassium, with average figures of 5 mmol/L, 4-5 mmol/L, and 10 mmol/L, respectively. The rectum has the highest potassium secretion, with an average of 30 mmol/L. However, the exact composition of potassium secretions varies depending on factors such as disease, serum aldosterone levels, and serum pH.
It is important to note that gastric potassium secretions are low, and hypokalaemia (low potassium levels) may occur in vomiting. However, this is usually due to renal wasting of potassium rather than potassium loss in vomit. Understanding the different levels of potassium secretion in the GI tract can be helpful in diagnosing and treating potassium-related disorders.
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This question is part of the following fields:
- Gastrointestinal System
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Question 3
Correct
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A 70-year-old woman is suspected of having a femoral hernia. Where is it most likely to be clinically identifiable?
Your Answer: Below and lateral to the pubic tubercle
Explanation:Femoral hernias emerge from the femoral canal situated below and to the side of the pubic tubercle. These hernias are more common in women due to their unique pelvic anatomy. Repairing femoral hernias is crucial as they pose a significant risk of strangulation.
Understanding the Femoral Canal
The femoral canal is a fascial tunnel located at the medial aspect of the femoral sheath. It contains both the femoral artery and femoral vein, with the canal lying medial to the vein. The borders of the femoral canal include the femoral vein laterally, the lacunar ligament medially, the inguinal ligament anteriorly, and the pectineal ligament posteriorly.
The femoral canal plays a significant role in allowing the femoral vein to expand, which facilitates increased venous return to the lower limbs. However, it can also be a site of femoral hernias, which occur when abdominal contents protrude through the femoral canal. The relatively tight neck of the femoral canal places these hernias at high risk of strangulation, making it important to understand the anatomy and function of this structure. Overall, understanding the femoral canal is crucial for medical professionals in diagnosing and treating potential issues related to this area.
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This question is part of the following fields:
- Gastrointestinal System
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Question 4
Correct
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A 10-year-old girl presents to her doctor with a 2-month history of flatulence, foul-smelling diarrhoea, and a weight loss of 2kg. Her mother reports observing greasy, floating stools during this time.
During the examination, the patient appears to be in good health. There are no palpable masses or organomegaly during abdominal examination.
The child's serum anti-tissue transglutaminase antibodies are found to be elevated. What is the most probable HLA type for this child?Your Answer: HLA-DQ2
Explanation:The HLA most commonly associated with coeliac disease is HLA-DQ2. HLA, also known as human leukocyte antigen or major histocompatibility complex, is expressed on self-cells in the body and plays a role in presenting antigens to the immune system. The child’s symptoms of coeliac disease include fatty, floaty stools (steatorrhoea), weight loss, and positive tissue transglutaminase antibodies.
HLA-A01 is not commonly associated with autoimmune conditions, but has been linked to methotrexate-induced liver cirrhosis.
HLA-B27 is associated with psoriatic arthritis, reactive arthritis, ankylosing spondylitis, and inflammatory bowel disease.
HLA-B35 is not commonly associated with autoimmune conditions.
Understanding Coeliac Disease
Coeliac disease is an autoimmune disorder that affects approximately 1% of the UK population. It is caused by sensitivity to gluten, a protein found in wheat, barley, and rye. Repeated exposure to gluten leads to villous atrophy, which causes malabsorption. Coeliac disease is associated with various conditions, including dermatitis herpetiformis and autoimmune disorders such as type 1 diabetes mellitus and autoimmune hepatitis. It is strongly linked to HLA-DQ2 and HLA-DQ8.
To diagnose coeliac disease, NICE recommends screening patients who exhibit signs and symptoms such as chronic or intermittent diarrhea, failure to thrive or faltering growth in children, persistent or unexplained gastrointestinal symptoms, prolonged fatigue, recurrent abdominal pain, sudden or unexpected weight loss, unexplained anemia, autoimmune thyroid disease, dermatitis herpetiformis, irritable bowel syndrome, type 1 diabetes, and first-degree relatives with coeliac disease.
Complications of coeliac disease include anemia, hyposplenism, osteoporosis, osteomalacia, lactose intolerance, enteropathy-associated T-cell lymphoma of the small intestine, subfertility, and unfavorable pregnancy outcomes. In rare cases, it can lead to esophageal cancer and other malignancies.
The diagnosis of coeliac disease is confirmed through a duodenal biopsy, which shows complete atrophy of the villi with flat mucosa and marked crypt hyperplasia, intraepithelial lymphocytosis, and dense mixed inflammatory infiltrate in the lamina propria. Treatment involves a lifelong gluten-free diet.
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This question is part of the following fields:
- Gastrointestinal System
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Question 5
Incorrect
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A 42-year-old woman presents to her GP with complaints of intermittent upper abdominal pain that worsens after eating. She denies having a fever and reports normal bowel movements. The pain is rated at 6/10 and is only slightly relieved by paracetamol. The GP suspects a blockage in the biliary tree. Which section of the duodenum does this tube open into, considering the location of the blockage?
Your Answer: Duodenojejunal flexure
Correct Answer: 2nd part of the duodenum
Explanation:The second segment of the duodenum is situated behind the peritoneum and contains the major and minor duodenal papillae.
Based on the symptoms described, the woman is likely experiencing biliary colic, which is characterized by intermittent pain that worsens after consuming fatty meals. Blockages in the biliary tree, typically caused by stones, can occur at any point, but in this case, it is likely in the cystic duct, as there is no mention of jaundice and the stool is normal.
The cystic duct joins with the right and left hepatic ducts to form the common bile duct, which then merges with the pancreatic duct to create the common hepatopancreatic duct. The major papilla, located in the second segment of the duodenum, is where these ducts empty into the duodenum. This segment is also situated behind the peritoneum.
Peptic ulcers affecting the duodenum are most commonly found in the first segment.
The third segment of the duodenum can be compressed by the superior mesenteric artery, leading to superior mesenteric artery syndrome, particularly in individuals with low body fat.
The fourth segment of the duodenum runs close to the abdominal aorta and can be compressed by an abdominal aortic aneurysm.
The ligament of Treitz attaches the duodenojejunal flexure to the diaphragm and is not associated with any particular pathology.
The retroperitoneal structures are those that are located behind the peritoneum, which is the membrane that lines the abdominal cavity. These structures include the duodenum (2nd, 3rd, and 4th parts), ascending and descending colon, kidneys, ureters, aorta, and inferior vena cava. They are situated in the back of the abdominal cavity, close to the spine. In contrast, intraperitoneal structures are those that are located within the peritoneal cavity, such as the stomach, duodenum (1st part), jejunum, ileum, transverse colon, and sigmoid colon. It is important to note that the retroperitoneal structures are not well demonstrated in the diagram as the posterior aspect has been removed, but they are still significant in terms of their location and function.
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This question is part of the following fields:
- Gastrointestinal System
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Question 6
Incorrect
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A 65-year-old patient loses 1.6L of fresh blood from their abdominal drain. Which of the following will not decrease?
Your Answer: Cardiac output
Correct Answer: Renin secretion
Explanation:Renin secretion is likely to increase when there is systemic hypotension leading to a decrease in renal blood flow. While the kidney can regulate its own blood flow within a certain range of systemic blood pressures, a reduction of 1.6 L typically results in an elevation of renin secretion.
Shock is a condition where there is not enough blood flow to the tissues. There are five main types of shock: septic, haemorrhagic, neurogenic, cardiogenic, and anaphylactic. Septic shock is caused by an infection that triggers a particular response in the body. Haemorrhagic shock is caused by blood loss, and there are four classes of haemorrhagic shock based on the amount of blood loss and associated symptoms. Neurogenic shock occurs when there is a disruption in the autonomic nervous system, leading to decreased vascular resistance and decreased cardiac output. Cardiogenic shock is caused by heart disease or direct myocardial trauma. Anaphylactic shock is a severe, life-threatening allergic reaction. Adrenaline is the most important drug in treating anaphylaxis and should be given as soon as possible.
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This question is part of the following fields:
- Gastrointestinal System
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Question 7
Incorrect
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A 63-year-old man with a history of alcohol abuse presents with recurrent epigastric pain. An OGD reveals the presence of varices in the lower esophagus. To prevent variceal bleeding, which medication would be the most suitable prophylactic option?
Your Answer: Warfarin
Correct Answer: Propranolol
Explanation:A non-cardioselective β blocker (NSBB) is the appropriate medication for prophylaxis against oesophageal bleeding in patients with varices. NSBBs work by causing splanchnic vasoconstriction, which reduces portal blood flow. Omeprazole, warfarin, and unfractionated heparin are not suitable options for this purpose.
Variceal haemorrhage is a serious condition that requires prompt and effective management. The initial treatment involves resuscitation of the patient, correction of clotting abnormalities, and administration of vasoactive agents such as terlipressin or octreotide. Prophylactic IV antibiotics are also recommended to reduce mortality in patients with liver cirrhosis. Endoscopic variceal band ligation is the preferred method for controlling bleeding, and the use of a Sengstaken-Blakemore tube or Transjugular Intrahepatic Portosystemic Shunt (TIPSS) may be necessary if bleeding cannot be controlled. However, TIPSS can lead to exacerbation of hepatic encephalopathy, which is a common complication.
To prevent variceal haemorrhage, prophylactic measures such as propranolol and endoscopic variceal band ligation (EVL) are recommended. Propranolol has been shown to reduce rebleeding and mortality compared to placebo. EVL is superior to endoscopic sclerotherapy and should be performed at two-weekly intervals until all varices have been eradicated. Proton pump inhibitor cover is given to prevent EVL-induced ulceration. NICE guidelines recommend offering endoscopic variceal band ligation for the primary prevention of bleeding for people with cirrhosis who have medium to large oesophageal varices.
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This question is part of the following fields:
- Gastrointestinal System
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Question 8
Correct
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A 32-year-old male patient is diagnosed with a peptic ulcer. What is the source of gastric acid secretion?
Your Answer: Parietal cells
Explanation:Gastric acid is released by parietal cells, while Brunner’s glands are located in the duodenum.
Understanding Gastric Secretions for Surgical Procedures
A basic understanding of gastric secretions is crucial for surgeons, especially when dealing with patients who have undergone acid-lowering procedures or are prescribed anti-secretory drugs. Gastric acid, produced by the parietal cells in the stomach, has a pH of around 2 and is maintained by the H+/K+ ATPase pump. Sodium and chloride ions are actively secreted from the parietal cell into the canaliculus, creating a negative potential across the membrane. Carbonic anhydrase forms carbonic acid, which dissociates, and the hydrogen ions formed by dissociation leave the cell via the H+/K+ antiporter pump. This leaves hydrogen and chloride ions in the canaliculus, which mix and are secreted into the lumen of the oxyntic gland.
There are three phases of gastric secretion: the cephalic phase, gastric phase, and intestinal phase. The cephalic phase is stimulated by the smell or taste of food and causes 30% of acid production. The gastric phase, which is caused by stomach distension, low H+, or peptides, causes 60% of acid production. The intestinal phase, which is caused by high acidity, distension, or hypertonic solutions in the duodenum, inhibits gastric acid secretion via enterogastrones and neural reflexes.
The regulation of gastric acid production involves various factors that increase or decrease production. Factors that increase production include vagal nerve stimulation, gastrin release, and histamine release. Factors that decrease production include somatostatin, cholecystokinin, and secretin. Understanding these factors and their associated pharmacology is essential for surgeons.
In summary, a working knowledge of gastric secretions is crucial for surgical procedures, especially when dealing with patients who have undergone acid-lowering procedures or are prescribed anti-secretory drugs. Understanding the phases of gastric secretion and the regulation of gastric acid production is essential for successful surgical outcomes.
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This question is part of the following fields:
- Gastrointestinal System
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Question 9
Correct
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A 38-year-old woman presents to her GP with a 6-month history of fatigue and weakness, with a recent increase in shortness of breath upon walking.
Past medical history - vitiligo.
Medications - over the counter multivitamins.
On examination - lung sounds were vesicular with equal air entry bilaterally; mild jaundice noticed in her sclera.
Hb 95 g/L Male: (135-180)
Female: (115 - 160)
Platelets 210 * 109/L (150 - 400)
WBC 6.0 * 109/L (4.0 - 11.0)
Vitamin B12 105 ng/L (200 - 900)
What is the underlying pathological process given the likely diagnosis?Your Answer: Autoimmune destruction of gastroparietal cells
Explanation:Pernicious anaemia is a condition where the body’s immune system attacks either the intrinsic factor or the gastroparietal cells, leading to a deficiency in vitamin B12 absorption. The patient’s history, examination, and blood results can provide clues to the diagnosis, such as fatigue, dyspnoea, mild jaundice, and low haemoglobin levels. The correct answer for the cause of pernicious anaemia is autoimmune destruction of gastroparietal cells, as intrinsic factor destruction is not an option. Autoimmune destruction of chief or goblet cells is not related to this condition. Ulcerative colitis may cause similar symptoms, but it is unlikely to affect vitamin B12 absorption and cause jaundice.
Pernicious anaemia is a condition that results in a deficiency of vitamin B12 due to an autoimmune disorder affecting the gastric mucosa. The term pernicious refers to the gradual and subtle harm caused by the condition, which often leads to delayed diagnosis. While pernicious anaemia is the most common cause of vitamin B12 deficiency, other causes include atrophic gastritis, gastrectomy, and malnutrition. The condition is characterized by the presence of antibodies to intrinsic factor and/or gastric parietal cells, which can lead to reduced vitamin B12 absorption and subsequent megaloblastic anaemia and neuropathy.
Pernicious anaemia is more common in middle to old age females and is associated with other autoimmune disorders such as thyroid disease, type 1 diabetes mellitus, Addison’s, rheumatoid, and vitiligo. Symptoms of the condition include anaemia, lethargy, pallor, dyspnoea, peripheral neuropathy, subacute combined degeneration of the spinal cord, neuropsychiatric features, mild jaundice, and glossitis. Diagnosis is made through a full blood count, vitamin B12 and folate levels, and the presence of antibodies.
Management of pernicious anaemia involves vitamin B12 replacement, usually given intramuscularly. Patients with neurological features may require more frequent doses. Folic acid supplementation may also be necessary. Complications of the condition include an increased risk of gastric cancer.
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This question is part of the following fields:
- Gastrointestinal System
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Question 10
Correct
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A 40-year-old female presents to the hepatology clinic with a 4-month history of abdominal pain, jaundice, and abdominal swelling. She has a medical history of systemic lupus erythematosus and is currently taking the combined oral contraceptive pill. During abdominal examination, a palpable mass is detected in the right upper quadrant and shifting dullness is observed. Further investigations reveal a high serum-ascites albumin gradient (> 11g/L) in a small amount of ascitic fluid that was collected for analysis. What is the most likely diagnosis?
Your Answer: Budd-Chiari syndrome
Explanation:A high SAAG gradient (> 11g/L) on ascitic tap indicates portal hypertension, but in this case, the correct diagnosis is Budd-Chiari syndrome. This condition occurs when the hepatic veins, which drain the liver, become blocked, leading to abdominal pain, ascites, and hepatomegaly. The patient’s medical history of systemic lupus erythematosus and combined oral contraceptive pill use put her at risk for blood clot formation, which likely caused the hepatic vein occlusion. The high SAAG gradient is due to increased hydrostatic pressure within the hepatic portal system. Other conditions that cause portal hypertension, such as right heart failure, liver metastasis, and alcoholic liver disease, also produce a high SAAG gradient. Acute pancreatitis, on the other hand, has a low SAAG gradient since it is not associated with increased portal pressure. Focal segmental glomerulosclerosis and Kwashiorkor also have low SAAG gradients.
Ascites is a medical condition characterized by the accumulation of abnormal amounts of fluid in the abdominal cavity. The causes of ascites can be classified into two groups based on the serum-ascites albumin gradient (SAAG) level. If the SAAG level is greater than 11g/L, it indicates portal hypertension, which is commonly caused by liver disorders such as cirrhosis, alcoholic liver disease, and liver metastases. Other causes of portal hypertension include cardiac conditions like right heart failure and constrictive pericarditis, as well as infections like tuberculous peritonitis. On the other hand, if the SAAG level is less than 11g/L, ascites may be caused by hypoalbuminaemia, malignancy, pancreatitis, bowel obstruction, and other conditions.
The management of ascites involves reducing dietary sodium and sometimes fluid restriction if the sodium level is less than 125 mmol/L. Aldosterone antagonists like spironolactone are often prescribed, and loop diuretics may be added if necessary. Therapeutic abdominal paracentesis may be performed for tense ascites, and large-volume paracentesis requires albumin cover to reduce the risk of complications. Prophylactic antibiotics may also be given to prevent spontaneous bacterial peritonitis. In some cases, a transjugular intrahepatic portosystemic shunt (TIPS) may be considered.
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This question is part of the following fields:
- Gastrointestinal System
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Question 11
Correct
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During a splenectomy, which structure will need to be divided in a 33-year-old man?
Your Answer: Short gastric vessels
Explanation:When performing a splenectomy, it is necessary to cut the short gastric vessels located in the gastrosplenic ligament. The mobilization of the splenic flexure of the colon may also be required, but it is unlikely that it will need to be cut. This is because it is a critical area that would require a complete colonic resection if it were divided.
Understanding the Anatomy of the Spleen
The spleen is a vital organ in the human body, serving as the largest lymphoid organ. It is located below the 9th-12th ribs and has a clenched fist shape. The spleen is an intraperitoneal organ, and its peritoneal attachments condense at the hilum, where the vessels enter the spleen. The blood supply of the spleen is from the splenic artery, which is derived from the coeliac axis, and the splenic vein, which is joined by the IMV and unites with the SMV.
The spleen is derived from mesenchymal tissue during embryology. It weighs between 75-150g and has several relations with other organs. The diaphragm is superior to the spleen, while the gastric impression is anterior, the kidney is posterior, and the colon is inferior. The hilum of the spleen is formed by the tail of the pancreas and splenic vessels. The spleen also forms the apex of the lesser sac, which contains short gastric vessels.
In conclusion, understanding the anatomy of the spleen is crucial in comprehending its functions and the role it plays in the human body. The spleen’s location, weight, and relations with other organs are essential in diagnosing and treating spleen-related conditions.
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This question is part of the following fields:
- Gastrointestinal System
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Question 12
Correct
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A 57-year-old man presents with recurrent episodes of urinary sepsis. He reports experiencing left iliac fossa pain repeatedly over the past few months and has noticed bubbles in his urine. A CT scan reveals a large inflammatory mass in the left iliac fossa, with no other abnormalities detected. What is the most likely diagnosis?
Ulcerative colitis
12%
Crohn's disease
11%
Mesenteric ischemia
11%
Diverticular disease
53%
Rectal cancer
13%
Explanation:
Recurrent diverticulitis can lead to the formation of local abscesses that may erode into the bladder, resulting in urinary sepsis and pneumaturia. This presentation would be atypical for Crohn's disease, and rectal cancer would typically be located more distally, with evidence of extra colonic disease present if the cancer were advanced.Your Answer: Diverticular disease
Explanation:Colovesical fistula is frequently caused by diverticular disease.
Repeated episodes of diverticulitis can lead to the formation of abscesses in the affected area. These abscesses may then erode into the bladder, causing urinary sepsis and pneumaturia. This presentation would be atypical for Crohn’s disease, and rectal cancer typically occurs in a more distal location. Additionally, if the case were malignant, there would likely be evidence of extra colonic disease and advanced progression.
Understanding Diverticular Disease
Diverticular disease is a common condition that involves the protrusion of the colon’s mucosa through its muscular wall. This typically occurs between the taenia coli, where vessels penetrate the muscle to supply the mucosa. Symptoms of diverticular disease include altered bowel habits, rectal bleeding, and abdominal pain. Complications can arise, such as diverticulitis, haemorrhage, fistula development, perforation and faecal peritonitis, abscess formation, and diverticular phlegmon.
To diagnose diverticular disease, patients may undergo a colonoscopy, CT cologram, or barium enema. However, it can be challenging to rule out cancer, especially in diverticular strictures. Acutely unwell surgical patients require a systematic investigation, including plain abdominal films and an erect chest x-ray to identify perforation. An abdominal CT scan with oral and intravenous contrast can help identify acute inflammation and local complications.
Treatment for diverticular disease includes increasing dietary fibre intake and managing mild attacks with antibiotics. Peri colonic abscesses require drainage, either surgically or radiologically. Recurrent episodes of acute diverticulitis requiring hospitalisation may indicate a segmental resection. Hinchey IV perforations, which involve generalised faecal peritonitis, require a resection and usually a stoma. This group has a high risk of postoperative complications and typically requires HDU admission. Less severe perforations may be managed by laparoscopic washout and drain insertion.
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This question is part of the following fields:
- Gastrointestinal System
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Question 13
Correct
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A 67-year-old male is undergoing an elective left colectomy for colon cancer on the left side. The left colic artery is responsible for supplying blood to both the upper and lower portions of the descending colon.
From which artery does the left colic artery originate?Your Answer: Inferior mesenteric artery
Explanation:The inferior rectal artery is a branch of the inferior mesenteric artery. It provides blood supply to the anal canal and the lower part of the rectum. It originates from the inferior mesenteric artery and runs downwards towards the anus, where it divides into several smaller branches.
The Inferior Mesenteric Artery: Supplying the Hindgut
The inferior mesenteric artery (IMA) is responsible for supplying the embryonic hindgut with blood. It originates just above the aortic bifurcation, at the level of L3, and passes across the front of the aorta before settling on its left side. At the point where the left common iliac artery is located, the IMA becomes the superior rectal artery.
The hindgut, which includes the distal third of the colon and the rectum above the pectinate line, is supplied by the IMA. The left colic artery is one of the branches that emerges from the IMA near its origin. Up to three sigmoid arteries may also exit the IMA to supply the sigmoid colon further down the line.
Overall, the IMA plays a crucial role in ensuring that the hindgut receives the blood supply it needs to function properly. Its branches help to ensure that the colon and rectum are well-nourished and able to carry out their important digestive functions.
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This question is part of the following fields:
- Gastrointestinal System
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Question 14
Correct
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In individuals with an annular pancreas, what is the most probable location of blockage?
Your Answer: The second part of the duodenum
Explanation:The pancreas is formed from two outgrowths of the foregut, namely the ventral and dorsal buds. As the rotation process takes place, the ventral bud merges with the gallbladder and bile duct, which are located nearby. However, if the pancreas fails to rotate properly, it may exert pressure on the duodenum, leading to obstruction. This condition is often caused by an abnormality in the development of the duodenum, and the most commonly affected area is the second part of the duodenum.
Anatomy of the Pancreas
The pancreas is located behind the stomach and is a retroperitoneal organ. It can be accessed surgically by dividing the peritoneal reflection that connects the greater omentum to the transverse colon. The pancreatic head is situated in the curvature of the duodenum, while its tail is close to the hilum of the spleen. The pancreas has various relations with other organs, such as the inferior vena cava, common bile duct, renal veins, superior mesenteric vein and artery, crus of diaphragm, psoas muscle, adrenal gland, kidney, aorta, pylorus, gastroduodenal artery, and splenic hilum.
The arterial supply of the pancreas is through the pancreaticoduodenal artery for the head and the splenic artery for the rest of the organ. The venous drainage for the head is through the superior mesenteric vein, while the body and tail are drained by the splenic vein. The ampulla of Vater is an important landmark that marks the transition from foregut to midgut and is located halfway along the second part of the duodenum. Overall, understanding the anatomy of the pancreas is crucial for surgical procedures and diagnosing pancreatic diseases.
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This question is part of the following fields:
- Gastrointestinal System
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Question 15
Incorrect
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A 52-year-old woman comes to the clinic complaining of distension and pain on the right side of her abdomen. She has a BMI of 30 kg/m² and has been diagnosed with type-2 diabetes mellitus. Upon conducting liver function tests, it was found that her Alanine Transaminase (ALT) levels were elevated. To investigate further, a liver ultrasound was ordered to examine the blood flow in and out of the liver. Which of the following blood vessels provides approximately one-third of the liver's blood supply?
Your Answer: Superior mesenteric artery
Correct Answer: Hepatic artery proper
Explanation:Structure and Relations of the Liver
The liver is divided into four lobes: the right lobe, left lobe, quadrate lobe, and caudate lobe. The right lobe is supplied by the right hepatic artery and contains Couinaud segments V to VIII, while the left lobe is supplied by the left hepatic artery and contains Couinaud segments II to IV. The quadrate lobe is part of the right lobe anatomically but functionally is part of the left, and the caudate lobe is supplied by both right and left hepatic arteries and lies behind the plane of the porta hepatis. The liver lobules are separated by portal canals that contain the portal triad: the hepatic artery, portal vein, and tributary of bile duct.
The liver has various relations with other organs in the body. Anteriorly, it is related to the diaphragm, esophagus, xiphoid process, stomach, duodenum, hepatic flexure of colon, right kidney, gallbladder, and inferior vena cava. The porta hepatis is located on the postero-inferior surface of the liver and transmits the common hepatic duct, hepatic artery, portal vein, sympathetic and parasympathetic nerve fibers, and lymphatic drainage of the liver and nodes.
The liver is supported by ligaments, including the falciform ligament, which is a two-layer fold of peritoneum from the umbilicus to the anterior liver surface and contains the ligamentum teres (remnant of the umbilical vein). The ligamentum venosum is a remnant of the ductus venosus. The liver is supplied by the hepatic artery and drained by the hepatic veins and portal vein. Its nervous supply comes from the sympathetic and parasympathetic trunks of the coeliac plexus.
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This question is part of the following fields:
- Gastrointestinal System
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Question 16
Incorrect
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A 24-year-old male patient visits the GP with recurring diarrhoea and urinary symptoms. The patient is currently undergoing tests for inflammatory bowel disease (IBD). He reports dysuria and describes his urine as dark brown and frothy. What aspect of IBD is likely responsible for these symptoms?
Your Answer: Crypt abscesses
Correct Answer: Fistula
Explanation:Fistulas are often seen in patients with Crohn’s disease due to the erosion of the submucosal layer, which can lead to full-thickness ulcers. If these ulcers penetrate the bowel and reach the bladder, they can create a pathway for undigested food to enter the bladder.
While bloody stool is commonly associated with ulcerative colitis (UC), it can also occur in Crohn’s disease. However, this symptom alone cannot explain the patient’s urinary tract infections or the passing of tomato skin.
Crypt abscesses are not present in Crohn’s disease and are only associated with UC. Therefore, they cannot explain the patient’s symptoms.
Goblet cell loss, which refers to the loss of mucin-secreting cells in the intestine, is only seen in UC and not in Crohn’s disease.
Inflammatory bowel disease (IBD) is a condition that includes two main types: Crohn’s disease and ulcerative colitis. Although they share many similarities in terms of symptoms, diagnosis, and treatment, there are some key differences between the two. Crohn’s disease is characterized by non-bloody diarrhea, weight loss, upper gastrointestinal symptoms, mouth ulcers, perianal disease, and a palpable abdominal mass in the right iliac fossa. On the other hand, ulcerative colitis is characterized by bloody diarrhea, abdominal pain in the left lower quadrant, tenesmus, gallstones, and primary sclerosing cholangitis. Complications of Crohn’s disease include obstruction, fistula, and colorectal cancer, while ulcerative colitis has a higher risk of colorectal cancer than Crohn’s disease. Pathologically, Crohn’s disease lesions can be seen anywhere from the mouth to anus, while ulcerative colitis inflammation always starts at the rectum and never spreads beyond the ileocaecal valve. Endoscopy and radiology can help diagnose and differentiate between the two types of IBD.
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This question is part of the following fields:
- Gastrointestinal System
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Question 17
Incorrect
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A 44-year-old female presents to her GP with persistent gastro-oesophageal reflux disease and complains of a burning pain in her chest. She is referred to a gastroenterologist who performs an endoscopy with biopsy, leading to a diagnosis of Barrett's oesophagus. Explain the metaplasia that occurs in Barrett's oesophagus and its association with an increased risk of oesophageal cancer.
Barrett's oesophagus is characterized by the metaplasia of the lower oesophageal epithelium from stratified squamous to simple columnar epithelium. This change from the normal stratified squamous epithelium increases the risk of oesophageal cancer by 30-fold and is often caused by gastro-oesophageal reflux disease.Your Answer: Simple squamous epithelium to simple columnar
Correct Answer: Stratified squamous epithelium to simple columnar
Explanation:Barrett’s oesophagus is characterized by the transformation of the lower oesophageal epithelial cells from stratified squamous to simple columnar epithelium. This change from the normal stratified squamous epithelium increases the risk of oesophageal cancer by 30 times and is often associated with gastro-oesophageal reflux disease.
Metaplasia is a reversible process where differentiated cells transform into another cell type. This change may occur as an adaptive response to stress, where cells sensitive to adverse conditions are replaced by more resilient cell types. Metaplasia can be a normal physiological response, such as the transformation of cartilage into bone. The most common type of epithelial metaplasia involves the conversion of columnar cells to squamous cells, which can be caused by smoking or Schistosomiasis. In contrast, metaplasia from squamous to columnar cells occurs in Barrett’s esophagus. If the metaplastic stimulus is removed, the cells will revert to their original differentiation pattern. However, if the stimulus persists, dysplasia may develop. Although metaplasia is not directly carcinogenic, factors that predispose to metaplasia may induce malignant transformation. The pathogenesis of metaplasia involves the reprogramming of stem cells or undifferentiated mesenchymal cells present in connective tissue, which differentiate along a new pathway.
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This question is part of the following fields:
- Gastrointestinal System
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Question 18
Incorrect
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A 70-year-old man is admitted to the hospital for angiography after experiencing a recent NSTEMI. He has been smoking 20 cigarettes a day since he was 15 years old and complains of foot pain when walking. During his stay, he develops worsening abdominal pain and bloody stools. After receiving fluids, a CT scan reveals pneumatosis and abnormal wall enhancement, indicating ischaemic colitis. Which part of the bowel is typically affected in this condition?
Your Answer: Sigmoid colon
Correct Answer: Splenic flexure
Explanation:Ischaemic colitis commonly affects the splenic flexure, which is a watershed area for arterial supply from the superior and inferior mesenteric artery. The descending colon is supplied by the left colic branch of the inferior mesenteric artery, while the hepatic flexure is supplied by the right colic branch of the superior mesenteric artery. The rectum receives arterial blood from the inferior mesenteric artery, middle rectal artery (from internal iliac artery), and inferior rectal artery (from the internal pudendal artery). The sigmoid colon is the second most common site for ischaemic colitis and is also a watershed area known as ‘Sudeck’s point’.
Understanding Ischaemic Colitis
Ischaemic colitis is a condition that occurs when there is a temporary reduction in blood flow to the large bowel. This can cause inflammation, ulcers, and bleeding. The condition is more likely to occur in areas of the bowel that are located at the borders of the territory supplied by the superior and inferior mesenteric arteries, such as the splenic flexure.
When investigating ischaemic colitis, doctors may look for a sign called thumbprinting on an abdominal x-ray. This occurs due to mucosal edema and hemorrhage. It is important to diagnose and treat ischaemic colitis promptly to prevent complications and ensure a full recovery.
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This question is part of the following fields:
- Gastrointestinal System
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Question 19
Correct
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A 55-year-old man presents to the emergency department with haematemesis which he has never experienced before. He reports a 3 week history of intermittent dull pain in the upper left quadrant and, upon further inquiry, he mentions that he believes he has been losing weight but he doesn't weigh himself often as he has always been in good shape. Other than a badly sprained ankle 10 weeks ago, for which he admits he is still taking ibuprofen, he has no medical conditions and is not taking any regular medication. He is a non-smoker and only drinks alcohol occasionally. What is the most probable cause of the patient's haematemesis?
Your Answer: Peptic ulcer
Explanation:Peptic ulcer is a frequent cause of haematemesis in patients who have been using NSAIDs extensively, as seen in this patient’s case. Peptic ulcers can manifest with various symptoms such as haematemesis, abdominal pain, nausea, weight loss, and acid reflux. Typically, the pain subsides when the patient eats or drinks.
Although weight loss can be a sign of malignancy, this patient has few risk factors (over 55 years old, smoker, high alcohol consumption, and obesity).
Any instance of repeated forceful vomiting can lead to a mallory-weiss tear, which presents as painful episodes of haematemesis.
Oesophageal varices are expected in patients with a history of alcohol abuse and usually present with signs of chronic liver disease.
Hereditary telangiectasia usually presents with a positive family history and telangiectasia around the lips, tongue, or mucus membranes. Epistaxis is a common symptom of this vascular malformation.
Helicobacter pylori: A Bacteria Associated with Gastrointestinal Problems
Helicobacter pylori is a type of Gram-negative bacteria that is commonly associated with various gastrointestinal problems, particularly peptic ulcer disease. This bacterium has two primary mechanisms that allow it to survive in the acidic environment of the stomach. Firstly, it uses its flagella to move away from low pH areas and burrow into the mucous lining to reach the epithelial cells underneath. Secondly, it secretes urease, which converts urea to NH3, leading to an alkalinization of the acidic environment and increased bacterial survival.
The pathogenesis mechanism of Helicobacter pylori involves the release of bacterial cytotoxins, such as the CagA toxin, which can disrupt the gastric mucosa. This bacterium is associated with several gastrointestinal problems, including peptic ulcer disease, gastric cancer, B cell lymphoma of MALT tissue, and atrophic gastritis. However, its role in gastro-oesophageal reflux disease (GORD) is unclear, and there is currently no role for the eradication of Helicobacter pylori in GORD.
The management of Helicobacter pylori infection involves a 7-day course of treatment with a proton pump inhibitor, amoxicillin, and either clarithromycin or metronidazole. For patients who are allergic to penicillin, a proton pump inhibitor, metronidazole, and clarithromycin are used instead.
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This question is part of the following fields:
- Gastrointestinal System
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Question 20
Correct
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A 50-year-old man arrives at the emergency department complaining of haematemesis. He appears unkempt and emits a strong odour of alcohol. During the examination, the physician notes the presence of palmar erythema, spider naevi, and jaundiced sclera. The patient's vital signs indicate tachycardia and tachypnea, with a blood pressure of 90/55 mmHg. What is the probable reason for the patient's haematemesis?
Your Answer: Oesophageal varices
Explanation:The patient is exhibiting signs of shock, possibly due to hypovolemia caused by significant blood loss from variceal bleeding. The patient’s physical examination reveals indications of chronic liver disease, making oesophageal varices the most probable cause of the bleeding. Mallory-Weiss tear, which causes painful episodes of haematemesis, usually occurs after repeated forceful vomiting, but there is no evidence of vomiting in this patient. Peptic ulcers typically affect older patients with abdominal pain and those taking non-steroidal anti-inflammatory drugs.
Less Common Oesophageal Disorders
Plummer-Vinson syndrome is a condition characterized by a triad of dysphagia, glossitis, and iron-deficiency anaemia. Dysphagia is caused by oesophageal webs, which are thin membranes that form in the oesophagus. Treatment for this condition includes iron supplementation and dilation of the webs.
Mallory-Weiss syndrome is a disorder that occurs when severe vomiting leads to painful mucosal lacerations at the gastroesophageal junction, resulting in haematemesis. This condition is common in alcoholics.
Boerhaave syndrome is a severe disorder that occurs when severe vomiting leads to oesophageal rupture. This condition requires immediate medical attention.
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This question is part of the following fields:
- Gastrointestinal System
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Question 21
Incorrect
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A 33-year-old man visits his doctor with complaints of occasional rectal bleeding, diarrhea, and fatigue. He reports that his symptoms have been progressively worsening for the past year, and he is worried because his father was diagnosed with colorectal cancer at the age of 56.
Upon referral for a colonoscopy, the patient is found to have numerous benign polyps in his large colon.
Which gene mutation is linked to this condition?Your Answer: TP53
Correct Answer: APC
Explanation:Familial adenomatous polyposis (FAP) is caused by a mutation in the adenomatous polyposis coli gene (APC), which is a tumour suppressor gene. This hereditary condition is characterised by the presence of numerous benign polyps in the colon, which increases the risk of developing colon cancer. Cystic fibrosis is caused by a mutation in the CFTR gene, which is not related to the symptoms of FAP. Hereditary non-polyposis colorectal cancer (HNPCC) is associated with mutations in DNA mismatch repair genes such as MLH1, but it does not involve the development of numerous benign polyps. Li-Fraumeni syndrome is a rare disease caused by a mutation in the TP53 tumour suppressor gene, which is associated with the development of various cancers. Gilbert’s syndrome is caused by a mutation in a different gene and is not related to FAP.
Colorectal cancer can be classified into three types: sporadic, hereditary non-polyposis colorectal carcinoma (HNPCC), and familial adenomatous polyposis (FAP). Sporadic colon cancer is believed to be caused by a series of genetic mutations, including allelic loss of the APC gene, activation of the K-ras oncogene, and deletion of p53 and DCC tumor suppressor genes. HNPCC, which is an autosomal dominant condition, is the most common form of inherited colon cancer. It is caused by mutations in genes involved in DNA mismatch repair, leading to microsatellite instability. The most common genes affected are MSH2 and MLH1. Patients with HNPCC are also at a higher risk of other cancers, such as endometrial cancer. The Amsterdam criteria are sometimes used to aid diagnosis of HNPCC. FAP is a rare autosomal dominant condition that leads to the formation of hundreds of polyps by the age of 30-40 years. It is caused by a mutation in the APC gene. Patients with FAP are also at risk of duodenal tumors. A variant of FAP called Gardner’s syndrome can also feature osteomas of the skull and mandible, retinal pigmentation, thyroid carcinoma, and epidermoid cysts on the skin. Genetic testing can be done to diagnose HNPCC and FAP, and patients with FAP generally have a total colectomy with ileo-anal pouch formation in their twenties.
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This question is part of the following fields:
- Gastrointestinal System
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Question 22
Incorrect
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A 35-year-old man presents to the hospital with joint pain, fatigue, unintentional weight loss, and diffuse abdominal pain. He is also complaining of polyuria and polydipsia. He is somewhat of a loner, who lives alone and has never visited a doctor before. He is an orphan who does not know anything about his biological parents.
Upon examination, tenderness is noticed in the right upper quadrant, and the presence of ascites on percussion. Additionally, this man's skin has a grey-discoloration. He is diagnosed with cirrhosis and chronic pancreatitis resulting in type 1 diabetes mellitus. An investigation is launched to determine the cause of his condition.
What is the most probable cause of the patient's cirrhosis and chronic pancreatitis?Your Answer: Excessive alcohol intake
Correct Answer: Hereditary haemochromatosis
Explanation:Chronic pancreatitis can be attributed to genetic factors such as cystic fibrosis and hereditary haemochromatosis. In the case of a man with a slate-grey skin tone, it was discovered that he had developed cirrhosis due to untreated hereditary haemochromatosis. Despite being a hereditary condition, the man was never diagnosed earlier as he was an orphan and a recluse. Excessive alcohol consumption can also lead to cirrhosis and pancreatitis, but it would not explain the grey skin. Chronic hepatitis B infection is another cause of cirrhosis, but it would not be the reason for the pancreatitis.
Understanding Chronic Pancreatitis
Chronic pancreatitis is a condition characterized by inflammation that can affect both the exocrine and endocrine functions of the pancreas. While alcohol excess is the leading cause of this condition, up to 20% of cases are unexplained. Other causes include genetic factors such as cystic fibrosis and haemochromatosis, as well as ductal obstruction due to tumors, stones, and structural abnormalities.
Symptoms of chronic pancreatitis include pain that worsens 15 to 30 minutes after a meal, steatorrhoea, and diabetes mellitus. Abdominal x-rays and CT scans are used to detect pancreatic calcification, which is present in around 30% of cases. Functional tests such as faecal elastase may also be used to assess exocrine function if imaging is inconclusive.
Management of chronic pancreatitis involves pancreatic enzyme supplements, analgesia, and antioxidants. While there is limited evidence to support the use of antioxidants, one study suggests that they may be beneficial in early stages of the disease. Overall, understanding the causes and symptoms of chronic pancreatitis is crucial for effective management and treatment.
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This question is part of the following fields:
- Gastrointestinal System
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Question 23
Incorrect
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A 67-year-old man is brought to the emergency department after a fall and head injury he sustained while walking home. He has a history of multiple similar admissions related to alcohol excess. During his hospital stay, his blood sugar levels remain consistently high and he appears disheveled. There is no significant past medical history.
What could be the probable reason for the patient's elevated blood glucose levels?Your Answer: Type 2 diabetes mellitus
Correct Answer: Destruction of islets of Langerhans cells
Explanation:Chronic pancreatitis can cause diabetes as it destroys the islet of Langerhans cells in the pancreas. This patient has a history of recurrent admissions due to alcohol-related falls, indicating excessive alcohol intake, which is the most common risk factor for chronic pancreatitis. A high sugar diet alone should not consistently elevated blood sugar levels if normal insulin control mechanisms are functioning properly. Gastrointestinal bleeding and the stress response to injury would not immediately raise blood sugar levels. In this case, the patient’s alcohol intake suggests chronic pancreatitis as the cause of elevated blood sugar levels rather than type 2 diabetes mellitus.
Understanding Chronic Pancreatitis
Chronic pancreatitis is a condition characterized by inflammation that can affect both the exocrine and endocrine functions of the pancreas. While alcohol excess is the leading cause of this condition, up to 20% of cases are unexplained. Other causes include genetic factors such as cystic fibrosis and haemochromatosis, as well as ductal obstruction due to tumors, stones, and structural abnormalities.
Symptoms of chronic pancreatitis include pain that worsens 15 to 30 minutes after a meal, steatorrhoea, and diabetes mellitus. Abdominal x-rays and CT scans are used to detect pancreatic calcification, which is present in around 30% of cases. Functional tests such as faecal elastase may also be used to assess exocrine function if imaging is inconclusive.
Management of chronic pancreatitis involves pancreatic enzyme supplements, analgesia, and antioxidants. While there is limited evidence to support the use of antioxidants, one study suggests that they may be beneficial in early stages of the disease. Overall, understanding the causes and symptoms of chronic pancreatitis is crucial for effective management and treatment.
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This question is part of the following fields:
- Gastrointestinal System
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Question 24
Incorrect
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A 65-year-old male patient undergoes liver resection surgery and encounters uncontrolled hepatic bleeding. To interrupt the blood flow, the surgeon performs the 'Pringle manoeuvre' by clamping the hepatic artery, portal vein, and common bile duct, which form the anterior boundary of the epiploic foramen. What other vessel serves as a boundary in this area?
Your Answer: Common hepatic artery
Correct Answer: Inferior vena cava
Explanation:The inferior vena cava serves as the posterior boundary of the epiploic foramen. The anterior boundary is formed by the hepatoduodenal ligament, which contains the bile duct, portal vein, and hepatic artery. The first part of the duodenum forms the inferior boundary, while the caudate process of the liver forms the superior boundary.
The Epiploic Foramen and its Boundaries
The epiploic foramen is a small opening in the peritoneum that connects the greater and lesser sacs of the abdomen. It is located posterior to the liver and anterior to the inferior vena cava. The boundaries of the epiploic foramen include the bile duct to the right, the portal vein behind, and the hepatic artery to the left. The inferior boundary is the first part of the duodenum, while the superior boundary is the caudate process of the liver.
During liver surgery, bleeding can be controlled by performing a Pringles manoeuvre. This involves placing a vascular clamp across the anterior aspect of the epiploic foramen, which occludes the common bile duct, hepatic artery, and portal vein. This technique is useful in preventing excessive bleeding during liver surgery and can help to ensure a successful outcome.
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This question is part of the following fields:
- Gastrointestinal System
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Question 25
Incorrect
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Which of the following is not an extraintestinal manifestation of Crohn's disease?
Your Answer: Aphthous ulcers
Correct Answer: Erythema multiforme
Explanation:Understanding Crohn’s Disease
Crohn’s disease is a type of inflammatory bowel disease that can affect any part of the digestive tract, from the mouth to the anus. The exact cause of Crohn’s disease is unknown, but there is a strong genetic component. Inflammation occurs in all layers of the affected area, which can lead to complications such as strictures, fistulas, and adhesions.
Symptoms of Crohn’s disease typically appear in late adolescence or early adulthood and can include non-specific symptoms such as weight loss and lethargy, as well as more specific symptoms like diarrhea, abdominal pain, and perianal disease. Extra-intestinal features, such as arthritis, erythema nodosum, and osteoporosis, are also common in patients with Crohn’s disease.
To diagnose Crohn’s disease, doctors may look for raised inflammatory markers, increased faecal calprotectin, anemia, and low levels of vitamin B12 and vitamin D. It’s important to note that Crohn’s disease shares some features with ulcerative colitis, another type of inflammatory bowel disease, but there are also important differences between the two conditions. Understanding the symptoms and diagnostic criteria for Crohn’s disease can help patients and healthcare providers manage this chronic condition more effectively.
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This question is part of the following fields:
- Gastrointestinal System
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Question 26
Correct
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A 26-year-old male presented with weight loss, cramping abdominal pain, and bloody diarrhea. During colonoscopy, a diffusely red and friable mucosa was observed in the rectum and sigmoid colon, while the mucosa was normal in the proximal region. Over time, the disease progressed to involve most of the colon, except for the ileum. After several years, a colonic biopsy revealed high grade epithelial dysplasia. What was the probable initial diagnosis?
Your Answer: Ulcerative colitis
Explanation:Ulcerative colitis advances from the distal to proximal regions in a progressive manner, leading to dysplastic changes over time. These endoscopic observations necessitate frequent endoscopic monitoring, and if a colonic mass is present, a pancproctocolectomy is typically recommended.
Understanding Ulcerative Colitis
Ulcerative colitis is a type of inflammatory bowel disease that causes inflammation in the rectum and spreads continuously without going beyond the ileocaecal valve. It is most commonly seen in people aged 15-25 years and 55-65 years. The symptoms of ulcerative colitis are insidious and intermittent, including bloody diarrhea, urgency, tenesmus, abdominal pain, and extra-intestinal features. Diagnosis is done through colonoscopy and biopsy, but in severe cases, a flexible sigmoidoscopy is preferred to avoid the risk of perforation. The typical findings include red, raw mucosa that bleeds easily, widespread ulceration with preservation of adjacent mucosa, and inflammatory cell infiltrate in lamina propria. Extra-intestinal features of inflammatory bowel disease include arthritis, erythema nodosum, episcleritis, osteoporosis, uveitis, pyoderma gangrenosum, clubbing, and primary sclerosing cholangitis. Ulcerative colitis is linked with sacroiliitis, and a barium enema can show the whole colon affected by an irregular mucosa with loss of normal haustral markings.
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This question is part of the following fields:
- Gastrointestinal System
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Question 27
Correct
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A 25-year-old male has been referred to the clinic due to a family history of colorectal cancer. Genetic testing revealed a mutation of the APC gene, and a colonoscopy is recommended. What is the probable outcome of the procedure?
Your Answer: Multiple colonic adenomas
Explanation:Familial adenomatous polyposis coli is characterized by the presence of multiple colonic adenomas, which are caused by mutations in the APC gene.
Polyposis syndromes are a group of genetic disorders that cause the development of multiple polyps in the colon and other parts of the gastrointestinal tract. These polyps can increase the risk of developing cancer, and therefore, early detection and management are crucial. There are several types of polyposis syndromes, each with its own genetic defect, features, and associated disorders.
Familial adenomatous polyposis (FAP) is caused by a mutation in the APC gene and is characterized by the development of over 100 colonic adenomas, with a 100% risk of cancer. Screening and management involve regular colonoscopies and resectional surgery if polyps are found. FAP is also associated with gastric and duodenal polyps and abdominal desmoid tumors.
MYH-associated polyposis is caused by a biallelic mutation of the MYH gene and is associated with multiple colonic polyps and an increased risk of right-sided cancers. Attenuated phenotype can be managed with regular colonoscopies, while resection and ileoanal pouch reconstruction are recommended for those with multiple polyps.
Peutz-Jeghers syndrome is caused by a mutation in the STK11 gene and is characterized by multiple benign intestinal hamartomas, episodic obstruction, and an increased risk of GI cancers. Screening involves annual examinations and pan-intestinal endoscopy every 2-3 years.
Cowden disease is caused by a mutation in the PTEN gene and is characterized by macrocephaly, multiple intestinal hamartomas, and an increased risk of cancer at any site. Targeted individualized screening is recommended, with extra surveillance for breast, thyroid, and uterine cancers.
HNPCC (Lynch syndrome) is caused by germline mutations of DNA mismatch repair genes and is associated with an increased risk of colorectal, endometrial, and gastric cancers. Colonoscopies every 1-2 years from age 25 and consideration of prophylactic surgery are recommended, along with extra colonic surveillance.
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This question is part of the following fields:
- Gastrointestinal System
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Question 28
Incorrect
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A 16-year-old female was admitted to the paediatric unit with a history of anorexia nervosa and a body mass index of 16kg/m². Despite being uncooperative initially, she has shown improvement in her willingness to participate with the team. However, she now presents with complaints of abdominal pain and weakness. Upon blood testing, the following results were obtained:
Hb 125 g/L Male: (135-180) Female: (115 - 160)
Platelets 180 * 109/L (150 - 400)
WBC 4.5 * 109/L (4.0 - 11.0)
Na+ 138 mmol/L (135 - 145)
K+ 3.2 mmol/L (3.5 - 5.0)
Bicarbonate 26 mmol/L (22 - 29)
Urea 5 mmol/L (2.0 - 7.0)
Creatinine 70 µmol/L (55 - 120)
Calcium 2.1 mmol/L (2.1-2.6)
Phosphate 0.5 mmol/L (0.8-1.4)
Magnesium 0.6 mmol/L (0.7-1.0)
What is the likely cause of the patient's abnormal blood results?Your Answer: Extended period of low calories and vitamins
Correct Answer: Extended period of low calories then high carbohydrate intake
Explanation:Refeeding syndrome can occur in patients who have experienced prolonged catabolism and then suddenly switch to carbohydrate metabolism. This can lead to a rapid uptake of phosphate, potassium, and magnesium into the cells, caused by spikes in insulin and glucose. Patients with low BMI and poor nutritional intake over a long period of time are at a higher risk. Taking vitamin tablets would not affect blood results, but excessive intake can result in hypervitaminosis. While exogenous insulin could also cause this syndrome, there is no indication that the patient has taken it. To reduce the risk of refeeding syndrome, some patients may be advised to follow initial high-fat, low-carbohydrate diets.
Understanding Refeeding Syndrome
Refeeding syndrome is a condition that occurs when a person who has been starved for an extended period suddenly begins to eat again. This metabolic abnormality is caused by the abrupt switch from catabolism to carbohydrate metabolism. The consequences of refeeding syndrome include hypophosphataemia, hypokalaemia, hypomagnesaemia, and abnormal fluid balance, which can lead to organ failure.
To prevent refeeding syndrome, it is important to identify patients who are at high risk of developing the condition. According to guidelines produced by NICE in 2006, patients are considered high-risk if they have a BMI of less than 16 kg/m2, have experienced unintentional weight loss of more than 15% over 3-6 months, have had little nutritional intake for more than 10 days, or have hypokalaemia, hypophosphataemia, or hypomagnesaemia prior to feeding (unless high).
If a patient has two or more of the following risk factors, they are also considered high-risk: a BMI of less than 18.5 kg/m2, unintentional weight loss of more than 10% over 3-6 months, little nutritional intake for more than 5 days, or a history of alcohol abuse, drug therapy (including insulin, chemotherapy, diuretics, and antacids).
To prevent refeeding syndrome, NICE recommends that patients who haven’t eaten for more than 5 days should be re-fed at no more than 50% of their requirements for the first 2 days. By following these guidelines, healthcare professionals can help prevent the potentially life-threatening consequences of refeeding syndrome.
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This question is part of the following fields:
- Gastrointestinal System
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Question 29
Incorrect
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A 67-year-old male is receiving treatment for his colorectal cancer from the oncology team at his nearby hospital. What type of colorectal carcinoma is most frequently encountered?
Your Answer: Squamous cell carcinoma
Correct Answer: Adenocarcinoma
Explanation:The most common type of colorectal cancer is adenocarcinoma, which originates from the mucosal lining of the colon. Initially, it develops as a benign adenoma from glandular cells of the mucosa, which later transforms into a malignant form.
Squamous cell carcinoma arises from squamous cells, which are not present in the colon. Ductal carcinoma is a breast cancer that originates from ductal cells. Basal cell carcinoma is a type of skin cancer, while mesothelioma is a malignancy that affects the mesothelium, commonly found in the lining of the chest wall.
Colorectal cancer is a prevalent type of cancer in the UK, ranking third in terms of frequency and second in terms of cancer-related deaths. Every year, approximately 150,000 new cases are diagnosed, and 50,000 people die from the disease. The cancer can occur in different parts of the colon, with the rectum being the most common location, accounting for 40% of cases. The sigmoid colon follows closely, with 30% of cases, while the descending colon has only 5%. The transverse colon has 10% of cases, and the ascending colon and caecum have 15%.
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This question is part of the following fields:
- Gastrointestinal System
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Question 30
Incorrect
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A 55-year-old male visits his doctor complaining of abdominal pain, occasional vomiting of blood, and significant weight loss over the past two months. After undergoing a gastroscopy, which reveals multiple gastric ulcers and thickened gastric folds, the doctor suspects the presence of a gastrinoma and orders a secretin stimulation test (which involves administering exogenous secretin) to confirm the diagnosis.
What is the mechanism by which this administered hormone works?Your Answer: Stimulates gastric acid secretion
Correct Answer: Decreases gastric acid secretion
Explanation:Secretin is a hormone that is released by the duodenum in response to acidity. Its primary function is to decrease gastric acid secretion. It should be noted that the secretin stimulation test involves administering exogenous secretin, which paradoxically causes an increase in gastrin secretion. Secretin does not play a role in carbohydrate digestion, stimulation of gallbladder contraction, stimulation of gastric acid secretion (which is the function of gastrin), or stimulation of pancreatic enzyme secretion (which is another function of CCK).
Overview of Gastrointestinal Hormones
Gastrointestinal hormones play a crucial role in the digestion and absorption of food. These hormones are secreted by various cells in the stomach and small intestine in response to different stimuli such as the presence of food, pH changes, and neural signals.
One of the major hormones involved in food digestion is gastrin, which is secreted by G cells in the antrum of the stomach. Gastrin increases acid secretion by gastric parietal cells, stimulates the secretion of pepsinogen and intrinsic factor, and increases gastric motility. Another hormone, cholecystokinin (CCK), is secreted by I cells in the upper small intestine in response to partially digested proteins and triglycerides. CCK increases the secretion of enzyme-rich fluid from the pancreas, contraction of the gallbladder, and relaxation of the sphincter of Oddi. It also decreases gastric emptying and induces satiety.
Secretin is another hormone secreted by S cells in the upper small intestine in response to acidic chyme and fatty acids. Secretin increases the secretion of bicarbonate-rich fluid from the pancreas and hepatic duct cells, decreases gastric acid secretion, and has a trophic effect on pancreatic acinar cells. Vasoactive intestinal peptide (VIP) is a neural hormone that stimulates secretion by the pancreas and intestines and inhibits acid secretion.
Finally, somatostatin is secreted by D cells in the pancreas and stomach in response to fat, bile salts, and glucose in the intestinal lumen. Somatostatin decreases acid and pepsin secretion, decreases gastrin secretion, decreases pancreatic enzyme secretion, and decreases insulin and glucagon secretion. It also inhibits the trophic effects of gastrin and stimulates gastric mucous production.
In summary, gastrointestinal hormones play a crucial role in regulating the digestive process and maintaining homeostasis in the gastrointestinal tract.
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This question is part of the following fields:
- Gastrointestinal System
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